Fibre reinforced and syntactic foam filled polymer composites are known in the art and are commonly made by reacting a curable resin with a reactive diluent in the presence of a free radical initiator. Reinforcing materials such as glass fibre and functional fillers are also included in the formulations to provide dimensional stability and toughness. Typically, the curable resin is an unsaturated polyester resin and the reactive diluent is a vinyl monomer. However, other thermoset resins may be used, such as acrylic, vinyl ester resins, urethane or epoxy resins. Such reinforced composites are used in many applications, including mould making, architectural construction, automotive, aerospace, marine and for corrosion resistant products.
With the advent of CNC machining practices a growing number of mould manufacturers are turning to CNC processes to manufacture tooling plugs. Plugs generally are three dimensional templates from which composites moulds are fabricated. The plug may be an accurate and sturdy reproduction of the part to be moulded.
A typical historical process is as follows:
A block of rigid machineable foam or other substrate is placed under a CNC router or in a CNC workstation and is machined roughly to the shape of the part intended to be moulded. The block may be machined undersized so that a curable, machineable moulding compound can be applied at an overall thickness larger than the part and also thick enough to be structurally sound so that a mould of the machined shape can be made. In the industry this machined part from which the mould will be made is typically called a plug.
Moulding compounds currently in the market that are used to coat foam or wooden substrates are not always strong or durable enough in themselves to be used to create production moulds in their own right. Also, the composition of available moulding compounds is such that they tend to entrap air, and they leave voids that are exposed during machining of the final shape. These voids have to be hand filled and the filled surface hand shaped, which is labour intensive and usually difficult to perform.
The substrate that is often cheapest, lightest and easiest to machine is rigid foam. Two common foams in use are urethane and polystyrene foams. Urethane foam has the advantage of being solvent resistant but it is more expensive than polystyrene foam, especially in block form. Polystyrene foam, however, has at least one drawback in that the polystyrene foam is soluble in low molecular weight vinyl functional diluents, which may be overcome in some situations by adding a sealer to isolate the polystyrene foam from the effects of the low molecular weight diluents found in unsaturated polyester and vinyl ester resins, the resin system often used for making fibreglass plugs and moulds.
However, there are one or more shortcomings in the current art, for example:                a) The foam substrate needs to be laminated with fibreglass, which requires multiple material applications and preparations and hand consolidation.        b) Moulding compounds are usually not durable enough to be used as moulds in their own right and/or may have varying degrees of porosity.        c) Moulding compounds, due to the morphology are laid up with voids that require manual consolidation.        d) Direct to mould compounds are not resilient enough to handle higher volume production runs.        e) Existing methods of manufacture are costly in time, labour and/or cost of materials used.        
The present disclosure is directed, in part, to certain embodiments to overcome and/or ameliorate one or more of these disadvantages and/or to provide one or more useful alternatives and/or one or more additional advantages. Other advantages and/or benefits will become apparent from the discussion herein.